Increasing physical contact, total interest in what you are saying, high level of eye contact and no sign that shows any hurry, and active participation with you, are clear signals that your date is very interested in you. As anybody gets interested, he/she wants to increase intimacy and come nearer. These physical signals say that loudly. There will be no yawns. Rather the eyes will be shining and there will be a smile on the face. When you spot these signals, be sure that the other person loves to meet you and be with you. If you are equally interested, respond similarly and take that date forward to another level.
During dating, many times, people want to act nice and are not honest enough about their true feelings. Body language tells you what the truth is.